Highly reactive nanomineral assembly in soil colloids: Implications for paddy soil carbon storage

Xiaolei Huang; Wenjing Kang; Junjie Guo; Lei Wang; Haiyan Tang; Tingliang Li; Guanghui Yu; Wei Ran; Jianping Hong; Qirong Shen

doi:10.1016/j.scitotenv.2019.134728

Highly reactive nanomineral assembly in soil colloids: Implications for paddy soil carbon storage

Sci Total Environ. 2020 Feb 10:703:134728. doi: 10.1016/j.scitotenv.2019.134728. Epub 2019 Oct 31.

Authors

Xiaolei Huang¹, Wenjing Kang², Junjie Guo², Lei Wang³, Haiyan Tang², Tingliang Li⁴, Guanghui Yu⁵, Wei Ran⁶, Jianping Hong⁴, Qirong Shen²

Affiliations

¹ College of Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 080301, China; National Experimental Teaching Demonstration Center for Agricultural Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 080301, China; Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waster Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China.
² Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waster Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China.
³ Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Scientific Observation and Experimental Station of Arable Land Conservation of Jiangsu Province, Ministry of Agriculture and Rural Affairs, Nanjing 210014, China.
⁴ College of Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 080301, China; National Experimental Teaching Demonstration Center for Agricultural Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 080301, China.
⁵ Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China.
⁶ Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waster Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: ranwei@njau.edu.cn.

PMID: 31759715
DOI: 10.1016/j.scitotenv.2019.134728

Abstract

Mineral availability for carbon (C) binding is a key regulator of soil C storage, yet little is known about the highly reactive nanomineral assembly in the paddy soil colloids. Here, using high-resolution transmission electron microscopy (HRTEM), solid-state ²⁷Al and ²⁹Si nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS), we investigated the coordination nature of short-range-ordered (SRO) minerals in water-dispersible colloids that were isolated from the paddy soil under different six-year fertilization regimes. Our results showed that organic fertilization not only promoted the transformation of crystalline minerals to SRO phases in the bulk soils but also increased the concentrations of Fe, Al and Si in the soil colloids compared to chemical fertilization alone, and thus enhanced the accumulation of organic C in both the bulk soils and the soil colloids. The HRTEM images revealed that water-dispersible colloids in all soils, regardless of treatment, were composed of crystalline Fe nanominerals (with some Al/Si) and SRO-Al/Si nanominerals (with some Fe) associated with organic C. Furthermore, the combined results from the ²⁷Al and ²⁹Si NMR spectroscopy and XPS not only confirmed the presence of SRO-Al/Si nanoparticles as Si-rich allophane and phytolith but also demonstrated that organic fertilization promoted the transformation of aluminosilicates to SRO-Al/Si nanominerals in soil colloids. Together, these findings indicate that six-year organic fertilization promotes the formation of SRO minerals (e.g., ferrihydrite, Si-rich allophane and Fe-substituted allophane, as well as phytolith) in soils and modulates the assembly of organo-mineral complexes possibly by driving the biogeochemical cycles of Fe, Al, Si and specific organic ligands, thus contributing to the long-term storage of C in paddy soils.

Keywords: Organic fertilization; Organo-mineral complexes; Paddy soil carbon storage; Water-dispersible colloids.